Process to render leathers and furs water-resistant



United States Patent 3,402,071 PROQESS T RENDER LEATHERS AND FURS WATER-RESISTANT Rudi Heyden and Jiirgen Plapper, Dusseldorf, Germany,

assignors to Bohme Chemie Gesellschaft mit beschriinkter Haftung, Dusseldorf-Benrath, Germany, a corporation of Germany No Drawing. Filed July 2, 1964, Ser. No. 380,030 Claims priority, applicat i7lgn Germany, Aug. 8, 1963, B 039 4 Claims. oi. 117-141 ABSTRACT OF THE DISCLOSURE This effect is surprising and was in no way foreseeable, as no noteworthy water-resistance can be obtained with non-ethoxylated, long-chain fatty alcohols or fatty acids or with higher ethoxylated, long-chain fatty alcohols or fatty acids, to which 5 or more ethylene-oxide groups have been added. It is generally known to use ethoxylation products of fatty materials with 5 to 8 ethylene oxide radicals for the fat-liquoring process, but this measure effects only a very insignificant increase in water-resistance for retanned chrome upper leathers, and this eifect does not exceed the usual fat-liquoring.

The leathers, impregnated with the ethylene oxide addition products of the invention distinguish themselves by slight absorptive capacity and very slight permeability under drastic testing conditions, so that they are favorably suited for the impregnation of leathers subjected to heavy mechanical use, in particular sole leathers, shoe upper leather or also leathers for technical purposes.

The products, usable for the impregnation, are well known and can be prepared in the conventional way. They are preferably derived from fatty alcohols, fatty acids or fatty alcohols obtainable from the latter, all of which are derived from natural fats, oils and waxes. The following are suitable as fatty acids: decylenic acid, undecylenic acid, dodecylenic acid, oleic acid, erucic acid, linoleic acid and linolenic acid. As fatty alcohols, those having a chain length of 10 to 26 carbon atoms, for example, decenol, tetradecenol and oleyl alcohol are suitable. Examples for the derivatives of the unsaturated fatty acids or fatty alcohols used according to the invention are therefore addition products of 1 to 4 mols of ethylene oxide per 1 mol of the named fatty alcohols and fatty acids. Here a considerably improved effect can be attributed to the derivatives of the fatty alcohols. Besides, the ethylene oxide addition products of fatty alcohols and fatty acids, also analogous addition products of other compounds with unsaturated fatty radicals containing exchangeable hydrogen atoms bonded to nitrogen or sulfur, may be used, i.e. addition products of 1 to 4 mols of ethylene oxide for unsaturated fatty amines, fatty acid amides, unsaturated organic sulfamides, fatty mercaptans, etc.

As organic solvents, in which the impregnation agents are used in dissolved condition, the following are suitable: trichloroethylene, perchloroethylene, benzine toluene, isopropanol or other low-molecular alcohols, methyl-ethylketone, cyclohexanone, acetic acid butylester.

With the use of the agents of the invention, all types of leathers or even furs can be impregnated, for example alum-, chrome-, or combined chrome tanned leathers, and also leathers tanned with synthetic or vegetable tanning agents.

The treatment of the leathers is accomplished in the usual manner by brushing on, soaking, spraying or with the aid of application machines. For this purpose 5 to 40%, preferably 10 to 20% solutions in organic solvents are used. For the treatment process generally 2 to 25%, preferably 5 to 10% of the ethylene oxide addition products of the invention, based on the weight of the leather are required. Only benzine or alcohols are suitable as solvents for the treatment of impregnated upper leathers whose body colors are sensitive to chlorohydrocarbons. The impregnation of vegetable tanned sole leathers can be accomplished in a solution of trichloroethylene or perchloroethylene. Due to the non-inflammability of these solvents, considerable advantages result for the production of sole leathers in view of the usual working conditions.

The agents used according to the invention, can be employed favorably in combination with citric acid esters or citric acid amides which still have in the molecule at least one free carboxyl group and of which at least one of the esterification or amidation components contains one unsaturated, high-molecular, aliphatic hydrocarbon radical. Here, mixtures of the ethylene oxide addition products of the invention with mono-oleyl citric acid esters in organic solvents have given especially satisfactory results.

As already described the solutions are applied onto the leathers to be treated which subsequently are slowly dried in air or in drying chambers at slightly elevated temperature. For the spray process, solvent mixtures containing compounds of a higher boiling point, such as higher boiling benzine, toluene or xylene are suitable. By adding small quantities of mineral oils it can be achieved, that the impregnation agents during the spraying will not adhere too strongly to the leather surface, but will penetrate into the leather. Solvents with a low boiling point are not suitable in this case as they evaporate too fast during the spraying so that the impregnation agents precipitate mainly on the leather surface. Also with the use of the soaking process, the distribution of the impregnating agents in the leather may be adjusted by changing the percentage of solvents with a higher boiling point.

The treated leathers exhibit under static and dynamic conditions a high water-resistance and a very low absorptive capacity. In contrast to the frequently observed hardening of the leather, which occurs easily with the use of impregnation agents, the leathers remain soft and pliable and they are not detrimentally affected in regard to their coloring and finishing. It is possible to impregnate finished upper leathers of any desired tanning process as well as sole leathers. This impregnation method is of particular significance for modern, not fatted water-proof leathers.

The impregnation effect can be further intensified or be adjusted to special demands, in that in addition to the ethylene oxide addition products of the invention or their mixtures with the above named citric acid esters or the citric acid amides, also condensation products of alcoholates of multivalent metals, especially of aluminum, and of acid high-molecular derivatives of phosphoric acid, in particular of acid phosphoric acid esters of highmolecular, organic hydroxyl compounds may be used. The impregnation can result from an organic solution together with these agents, or consecutively in any desired sequence. A further improvement, especially in regard to the water-repellent effect on the leather surface, can be achieved when the agents of the invention or their mixtures with the other above mentioned impregnating agents are used together with silicone oils and/ or hard Waxes. As silicone oils for this purpose are those products commercially available under this name, and natural or synthetic wax products may be used as hard waxes, e.g. paraflin-, carnauba-, montan wax or esteror carbonamide waxes. The various components can be dissolved Without difficulty in the organic solvents or in the mixtures thereof.

The following specific examples are presented to illustrate the invention and to enable persons skilled in the art to better understand and practice the invention and are not intended to be limitative.

Example I 3 samples of a conventional dressed, water-proof leather were soaked for a period of minutes in benzine solutions of the impregnation agents according to the invention, listed below under (a) and (b) and (c).

(a) 20% benzine solution (boiling ranges 110 to 140 C.) of the addition product of 2 mols of ethylene oxide per 1 mol of a commercial oleylalcohol with an iodine number of to 55.

(b) 20% benzine solution (boiling ranges 110 to 140 C.) of the addition product of 2 mols of ethylene oxide per 1 mol of oleic acid.

(c) 20% benzine solution (boiling ranges 110 to 140 C.) of the mixture of an addition product of 2 mols of ethylene oxide per 1 mol of a commercial oleylalcohol with an iodine number of 50 to 55, with a monooleyl citric acid ester in a ratio of 1:2.

After slow drying in air, the treated samples and a sample of the water-proof leather not treated according to the invention were examined as to their absorption of water and their water-resistance, and the following values listed in the table below Were obtained.

Water absorption accord- 3 samples of a vegetable-tanned sole leather were soaked for a period of 10 minutes in 20% perchloroethylene solutions of the impregnation agents listed under (d) and (e) and (f).

(d) 20% perchloroethylene solution of an addition product of 2 mols of ethylene oxide per 1 mol of a commercial oleylalcohol with an iodine number of 50 to 55.

(e) 20% perchloroethylene solution of an addition product of 2 mols of ethylene oxide per 1 mol of oleic acid.

(f) 20% perchloroethylene solution of a mixture of an addition product of 2 mols of ethylene oxide per 1 mol of a commercial oleylalcohol with an iodine number of 50 to with mono-oleyl citric acid esters in a ratio of 1:2.

After the drying of a leather samples in air, theywere examined as to their Water-absorption and Water-re- 4' sistance, and the following values were obtained therefrom:

Water absorption according to KUBELKA in Water penetrapercent after tion-penetrometer test 30 min. 2 hrs. 24 hrs.

Untreated rel. sample 91 5 minutes. Sample (d) 27 32 43 100 minutes. Sample (o) 31 39 45 80 minutes. Sample (I) 27 38 42 minutes.

Example III Water penetration after bends Untreated leather 110 Oleic acid monoethanolamide 800 Oleic acid 3 ethylene oxide 4,500

Oleylamine 1,2-ethylene oxide 300 Oleylalcohol (iodine No. 50) 2 ethylene oxide 5,500 Oleylalcohol (iodine No. 70) 2 ethylene oxide 5,000 Oleylalcohol (iodine No. 85) 2 ethylene oxide 4,900 Oleylalcohol (iodine No. 50) 5 ethylene oxide 80 The table shows, besides the special suitability of the reaction product of oleylalcohol with small quantities of ethylene oxide, that a product with 5 mol of ethylene oxide shows at the least no effect, if not a deterioration.

While certain specified examples and preferred modes of practice of the invention have been set forth it will be understood that this is solely for the purpose of illustration and that various changes and modifications may be made without departing from the spirit of the disclosure and the scope of the appended claims.

We claim:

1. A method of rendering leather and furs water resistant which comprises impregnating leather and fur skins with a solution containing 5 to 40% by weight of an addition product of 1 to 4 moles of ethylene oxide and 1 mole of a compound selected from the group consisting of unsaturated fatty alcohols of 10 to 26' carbon atoms and unsaturated fatty acids of 10 to 22 carbon atoms in an inert organic solvent, the amount of solution used being 2 to 25% by weight, based on the material being impregnated, of the addition product.

2.. The method of claim 1 wherein the amount of the said addition product is from 5 to 10% based on the weight of the material being impregnated.

3. The method of claim 1 wherein the said composition also contains a material selected from the group consisting of silicone oils and hard waxes.

4. The method of claim 1 wherein the said composition also contains a monoester of citric acid and oleyl alcohol.

References Cited UNITED STATES PATENTS 2,799,599 7/1967 Koch 117-441 2,968,580 1/1961 Plapper et a1 117135.5 3,010,780 11/1961 Plapper et al. 11713.S XR 3,048,265 8/ 1962 Hackhel et al. 106-13 XR 3,106,478 10/ 1963 Heyden et al. 106287 JAMES A. SEIDLECK, Primary Examiner.

L. B. HAYES, Assistant Examiner. 

